I've done some examples of transposing Java code explaining various design patterns from the GoF book to Haskell, then seeing how it gets simpler when you have a couple of higher-level ideas from Haskell to work with. It could make a fun talk to present at a Java-centric conference, "today I'm going to teach you some Haskell." As a bonus, you get to see how the Java code deals with a tremendous amount of needless complexity.

For example, here's what I've written so far for the Visitor pattern:

https://gist.github.com/drostie/818c54ca5c8182143699a72da986...